1. Technical Field
The present invention relates to an antenna for a mobile communication system and a fabrication method thereof, and in particular to an antenna for a mobile communication system and a fabrication method thereof which are capable of enhancing a band width of a high frequency signal and simplifying an assembling process of an antenna by improving the structure of a helical antenna in a mobile communication system.
2. Background Art
Generally, an antenna is used for performing a wireless communication. Namely, a high frequency signal is applied from a modulator to an antenna, and a high frequency signal transmitted in the air is received through the antenna.
In order to enhance a transmission and receiving characteristic of an antenna, an impedance of an antenna and an impedance of a transceiver are matched in accordance with a high frequency signal which is transmitted and received for thereby preventing unnecessary emission and loss.
In addition, the antenna used for the mobile communication system is formed of a helical antenna and a rod antenna in an integrated construction. In the case that the rod antenna is received, the helical antenna is operated. In the case that the rod antenna is extracted, the rod antenna and helical antenna are engaged in parallel. The entire operation of the antenna is performed by the rod antenna.
In the above described antenna structure, the helical antenna includes a spring formed by winding a wire.
FIG. 1 is a view illustrating an antenna installed in a conventional wireless communication system. Here, reference numeral 10 represents a body of a mobile communication system, and 20 represents an antenna unit installed in the body 10 for transmitting and receiving a high frequency signal therethrough.
The antenna unit 20 includes a knob 21 by which the antenna is extracted and retracted by holding the same, an insulation portion 22, a helical antenna 23 having a spring 25 which is operated when the antenna engaged to the body 10 of the mobile communication system is received, and a Nixe2x80x94Ti wire 24 engaged in parallel with the helical antenna 23 when extracting the antenna and functioning as a rod antenna.
FIG. 2 is a view illustrating a helical antenna 23 in the antenna of FIG. 1. As shown therein, the helical antenna 23 includes a spring 25 formed of a wire having a circular cross section and diameter, and a metal rod 26 engaged with the spring 25, so that the lower portion of the spring 25 is wound onto the metal rod 26 by one turn.
In the conventional antenna, since the return loss which occurs when a high frequency signal is transmitted is about 7.5 dB, and the band width a coverage in the antenna is small, the communication quality is decreased in the case that the antenna is touched by a hand of a human, and there is a certain variation in the frequency at the time of communication. In addition, the conventional antenna has about 23.0xcexa9 impedance which is lower than 50xcexa9 of a reference value for thereby causing a mismatching. In addition, in the conventional art, the standing wave ratio is about 2.3 larger than the reference value 1, so that the power return ratio is about 15.5%. Therefore, the power loss of the antenna is increased.
Accordingly, it is an object of the present invention to provide an antenna for a mobile communication system and a fabrication method thereof which are capable of obtaining a lower return loss by improving the structure of a spring installed in a helical antenna, improving a communication quality even when an antenna is touched by a hand of a human or there is a certain variation in the frequency at the time of communication.
In order to achieve the above objects, there is provided an antenna for a mobile communication system which includes a spring of the helical antenna formed in such a manner that a wire having a certain diameter is pressed for thereby forming a plate shaped wire having a certain width, and the plate shaped wire having a certain width is wound by a certain number of turns.
In order to achieve the above objects, there is provided a fabrication method of an antenna for a mobile communication system which includes a first step for pressing a wire having a certain diameter, forming a plate shaped wire having a certain width, winding the plate shaped wire having a certain width by a certain number of turns and forming a spring of a helical antenna, a second step for inserting and soldering an upper end of a metal rod to a lower portion of the spring formed of a plate shaped wire and fixing the same, a third step for insert-molding a pipe in such a manner that a certain space is formed in the center portion in the spring and metal rod fixed in the second step and inserting a bobbin of the pipe, and a fourth step for inserting a + cutting portion to a lower portion of the metal rod and inserting the rod antenna in the space portion of the center portion.